Dyeing process



Dec. 13, 1927. 1,652,649 M. E. TICE 'DYEING PROCESS Filed Feb 28 1925 /QIJ INVENTOR.

A TTORNE YS of the dye liquor thereto.

Patented Dc. 13, 1927.

UNITED STATES PATENT oFl-ucE.

MERLIN E. TICE, OF WAPPINGERS FAIS, NEW YORK, ASSIGNOR TO DUTCHESSBLEACH- -ERY, INC., OF NEW YORK, N. Y.,

A CORPORATION OF NEW YORK.

DYEING raoeass Application med February as, 192s. serieu no. 12,31s.

This invention relates to dyeing processes and particularly to dyeingwith vat dyes, such as the indanthrenes and anthraqulnones and others. f

The principal object of the invention 1s to provide an economical,continuousl dyeing process of the kind described, securln betterpenetration and absorption of the ye 1n reduced form than attained byheretofore known processes while avoiding spottlng of the material byoxidized dye, produclng thereby an evenly dyed material 1n deep, lightor intermediate tones.

The invention accordingly comprises a process for applying dyes tomaterial which includes absorbing a reduced dye by the material, whileavoiding oxidation of the dye on the material prior to absorption, andpassing the material so treated into a second reduced dye bath.

In carrying out the invention in its pre-- ferred form, use ispreferably made of the apparatus shown in the accompanying drawing, inwhich Fig. 1 is a longitudinal sectional elevatlon take-n on the line1-1 of Fig. 2;

Fig. 2 is an end elevation looking from the left in Fig. 1, and

Fig. 3 represents a fragmentary enlarged detail view showing the firstpair of nip rollers with the screen of dye liquor expressed therebyflowing down the face of the cloth.

Referring now to this drawing, 1 designates a length of piece goods ofcotton, wool, silk or other material. In the preferred embodiment of theprocess the material'is of cotton, the various conditions for dyeingdescribed in the preferred embodiment being particularly adapted forcotton. 2 and 3 represent nip rollers, suitably mounted at the entranceend of the apparatus. The lower roller 3 adapted to bc, supplied withreduced dye liquor from a tank 5 through a pipe 6 terminating in thebath 4 and provided with a valve 7 adapted to control the rate of flowThe tank 5 is supported by piers 8 projecing from the frame 9. A valvedinlet pipe 10 admits dye liquor` into the tank and a valved pipe 11located dips -into a shallow bath 44 at the bottom of the tank may beused for drainage. A valved pipe 12 extending from the bottom of theshallow bath 4 is also provlded for drainage of this bath. The bath 4 1ssubstantially semi-cylindrical in form extending the length of theroller 3 and concentric therewith. A rod 13 supports a fin 14 runningthe length of the roller 3 and substantially parallel to its axis, risinfrom the bath of dye liquor on the side of t e bath at which the clothenters. The function of the iin 14 will be later explained.

An idler roll 15 ositioned to receive cloth passing between t e niprollers 2 and 3 is supported by the frame`9 to deliver cloth into .oneend of a tank having two compartments 16 and 17 separated by adiaphragm. Compartment 16 is adapted to be supplied with a dilutedreduced dye solution through a pipe 18 and is provided with a drainagepipe 19 at the bottom thereof for cleaning. Rolls 20 are positioned inthe compartment 16 so that cloth traveling thereover may zigzag back andyforth in substantially horizontal paths, being preferably submergedduring the entire zigzag motion. Mounted upon the diaphragm is a secondset of ni rollers 21 and 22, through which the clotli emerging from thebath in compartment 16Y passes into the end of the compartment 17adjacent the diaphragm. This compartment is provided with rollers 23preferably so arranged that the cloth passes up and down insubstantiallyV vertical lines while passing through the compartment. Therolls are so 'arranged that the cloth emerges from time to time from theliquid contained in compartment 17. The compartment is provided with aninlet pipe 24 for water preferably cold, though it may be heated, and anoutlet pi e 25. Mounted uponthe opposite end of tile compartment 17 is athird set of nip rollers 26 and 27 which deliver cloth from thecompartment on to a roll 28 which may be driven by means of a belt 29operated by a pulley 30 mounted on the shaft of roller 26, driven by anoutside source of power and driving roll 28 by means of a pulley 31mounted thereon.

In carrying` out the process in its preoccupies then in the tank 5, thevalve 7 1s glue.

ferred form, a solution containingthe ol- This solution is preferablymade by mixing approximately'330 pounds of water with the caustic sodaand adding to this the glue, the solution being brought to a boil. Theremaining Water is then added and the whole is cooled to approximately120 F. The dyestuff, with the soluble oil and pine oil, is boiled withabout pounds of Water and strained into the solution of caustic soda andThe hydrosulfite is then added to the mixture in powdered form and thewhole is stirred until thoroughly mixed which usually about ten minutes.This mixture being opened to fill the shallow bath 4 up to 1ts properdyeing level (see Fig. l).

The bath is replenished constantly thereafter with dye liquorfrom tank 5through pipe`6.

One end of a length of piece goods, for example, piece goods in openwidth designated in the drawing by the numeral 1, 1s

started through ythe apparatus from a box.

`The cloth is then threaded in the usual manner over the enlrance edgeof the bath 4, i

under the bar, 13, between the nip rollers 2 and 3, then over the roller15. It is then zigzagged back and forth over the rolls 20. From thecompartment 16 threading proceeds next between nip rollers 21 and 22,then into the compartment 17, and over the rollers 23. Through thiscompartment runs a stream of cooling Water preferably at about g roomtemperature, F. Emerging from this tank, the threading passes throughnip rollers 26, 27 and then on to the roll 28.

. The compartment 16 is meanwhile filled with a re-reducing solutionwhich is made up of the following ingredients b weight: water 1328 lbs.(approximatelyg, caustic soda 2 lbs., sodium hydrosulite 2 lbs., towhich is added 27 pounds of dye liquor from the stock tank 5. Power isapplied to roller 26, the cloth passed through the baths and rollersfollowing they path indicated in threading and is dyed.

It will be noted that the liquor in bath 4,

and compartment 16 constitute reduced dye' baths, Indanthrene Blue GCDhaving in this instance been chosen as the dye, the alkalinehydrosulfite having been, chosen as the reducing agent, and the othermaterials being employed as assists.

Of course, it

will beunderstood that various other` dyes may be substituted for thedyestul finentioned and that other reducing ag'ts vand assists maylikewise be employed. l

It is important to notice that the concentration of the dye bath in the'shallow bath 4 is much greater than in the compartment 16. In 4thepresent embodiment the con'- centration of the reduced dye fed to thebath 4 is approximately 1.2%, while that inthe com artment 16 has aconcentration of .02% o reduced dye, thus the concentrated liquor isabout sixty times as strong as themore dilute liquor in compartment 16.4 llt will be further noted that the quantity ofdye vliquor 'that thebath 4 is capable oi holding at any one time is relatively smali. inordinary practice about three gallons are contained in the bath whereasthe compartment 16 contains about one hundred and sixty gallons. rlhesmall capacit of the bath 4 insures rapid renewal of t e liquor thereinso that the chance for oxidation of this liquor by air, with consequentspotting of the cloth by the oxidized dyestui is substantially avoided.The capacity of the bath 4 is. determined by a consideration o thevariables present in the apparatus. These variables are- 1. The rate ofoxidation of the given dye taken at the temperature selected, and

2. The dye absorption constant of the material which, with the rate oftravel .of the material through the bath, gives the actual absorptionconstant or removal constant of the dye by the material.

lt we find, for instance, that at a given rate of travel the cloth"willabsorb say three gallons of liquid in half a minute and then if we findupon trial that ob'ectionable oxidation-sufficient to cause iiec vs ofoxidized dye to collect in `the bath-occurs in twice that time, then thecapacity of the dye tank may be three gallons, since three allons willbe removed from the tank by the cloth in halfa minute, which is'ashorter time than is required to oxidize that quantity of liquid. Inother words, the capacity is less than that vquantity of the givenreduced dye liquor which will just oxidize in the time required for thematerial to 'absorb the liquor from the bath 4. The How of fresh reduceddye liquor from the tank 5 is controlled by the valve 7, and ismaintained at such rate that the bath 4-reniains at ractically aconstant level. It will be note that some oxidation of the bath tal-:csplace duc to the liberation of'air from the cloth 1,

and occurs after the cloth meets the dye. Oxidation of the dye isthereby produced and a `foam forms containing fiecks of oxidized dye. Onaccount of this the fin 14 is provided, which acts as a sort of dashboard to prevent the foam from being carried downward and these dyelecks coming lll() preciably occur and it is not in contact with theentering cloth. Due to the pressure of rolls 2 and 3 on the cloth, ascreen or curtain of expressed excess dye liquor designated as 32 inFig. 3, continuously descends over the face of the cloth. This streamprevents the foam from touching the cloth on roll 3 while the fin 14prevents the foam from touching the cloth entering the bath 4. It willbe noted that absorption of the dye liquor takes place from the time thematerial passes into bath 4 and until it has been nipped by the niprollers, 2 and 3. This absor tion occurs under the screen of liquor 32 wich insures with the fink 14 that no oxidized dye unabsorbed by thefibre shall remain thereon.

The difference in concentration between the two reduced dye solutionsaccomplishes a surprising result, namely, that more dye can be caused topenetrate the fibre and hence deeper shades can be obtained, bysubjecting the cloth to the highly concentrated bath and then to thedilute re-reducing bath, than is possible with two baths of equal dyestrength. Furthermore under the conditions described, exhaustion of bath16 does not apnecessary to replenish this bath with fresh dye liquor.The two baths are preferably maintained at about 120o F. and the cloth,in passing through` is preferably below the surface of the liquor toprevent oxidation. The cloth then passing into the compartment 1T? iscooled down so that unequal oxidation does not occur when the cloth ison the roll 28,

as might occur owing to varying temperature of 'the inner and outerportions of such a roll produced by unequal heat radiation, if notpreviously cooled.

To insure absolute uniformity of distribution `of the leuco-dyeresulting from reducing the indanthrene or other dye absorbed by thefibre. the material, afterbe-ing wound np on the roll 28, may be runthrough a jig containing another reducing bath without dyestuff. Thisbath contains the following ingredients by weight: v

Lbs. Vater 200 Caustic soda 2 Hydrosulfite 2 Soap 2 This solution ismaintained at 120o F. After jigging six times the solution is rcplacedby cold water and the cloth is washed twice in this water. The cloth,whether treated iii the bath without dye or not, is next treated with anoxidizing medium, such as an acid sodium bichi'omate solution containingthe-following ingredients:

Lbs. Bichroiiiute, of soda 2 Acetic acid 28 Tw. strength 4 l later 300dyestuff is per ornied, as

'the various agencies,

the reducing bath containing preferably noJ l pointed out above, toinsure greater uniformity and. distribution of the leuco-dye throughoutthe cloth as well as to make the dye fast to a maximuni degree duringwashing. The subsequent treatment with acid sodium bichromate oxidizesthe leuco-dye to develop the lglpeb color produced by Indanthrene BlueAs pointed out above', the' invention is not limited to the particularkind of dye-bath employed but may be satisfactorily used where otherdyes which are developed on the fibre are employed. For example, I haveobtained highly satisfactory results employing various dyes of the Cibaclass-Ciba Blue 2B, of the .Cibanone class-Cibanone Bill Blue 8G, AlgolBrown R, Helindone Red B-N and Hydron Brown G. In addition, I ina yvaryrthe type of reducing agent as well as that of the dye. The amountof dyestuff added to 1 60 gallons (1328 lbs.) of water in tank 5 givenin the examples varies, of course, with the tone desired and with thecharacter of the dyestuff. In employing the various dyestuffs mentionedabove, I have used from 1 ounce to 3() pounds of color and the otheringredients employed have also been similarly varied. I have found ingeneral that the ratio ofthe dye concentration in the shallow bath tothat in the re-reducing bath effects good results when it is maintainedwithin about the proportions given in the example above. Satisfactoryresults have also been obtained by using other relative concentrations.

he processas described is arapid and economical one. It accomplishesfixation of the dye on the fibre with relatively little oxidation orspotting ofthe cloth and the fixa tion is accomplished, as pointed out,with relatively few passages of the cloth through the dye baths toproduce full shades. The cloth produced is a highly satisfactory productin appearance, feel and in fastness to such as light, milling. Soaping,washing and others.

As many apparently widely different einbodiments of this invention maybe made without departing from the spirit thereof, I do not intend tolimitmyself to the above specific description, except as' indicated inthe appended claims.

Having thus described my invention what vlli I claim and desire tosecure by Letters Patent is:

1. A rocess for applying Vat dyes to material w ich comprises absorbinga reduced vat dye by the material and assing the material so treatedWhile the ye is in a substantially reduced state into a second reduceddye bath of very materially less concentration than the first bath.

2. A process for appl ing vat dyesto material which comprises c ippingmaterial into a reduced vat dye bath. then under a stream of reduced dyeliquor while absorption takes place, then removing excess dye liquor andthen passing the material so treated While the dye is in a substantiallyreduced state into a second bath of reduced dye of less concentrationthan the first bath.

3. A process of applying vat dyes to material which comprises dipping alength of cloth into a. reduced Vat dye bath. then sul)- jecting thesame to a stream of reduced dye liquor While absorption takes place,then expressing excess dye liquor from the cloth. the excess dye li uorrunning over a succeeding ortion of t e cloth to form the stream of dlyeliquor mentioned. and then passing the cloth so treated while the dye isin a` substantially reduced state into a second bath of reduced dyeliquor of less concentration than the lirst bath.

4. A process for applying vat dyes which comprises dipping the materialto be dyed into a bath containing a reduced vat dye,

then passing the material so treated While the dye is in a substantiallyreduced state through a second reduced solution of the same dye whileheated and of less concentration, and passing the material from thesecond bath into a bath at a reduced temperature to check oxidation ofthe dye.

5. A process for applying yat dyes which comprises passing the materialto be dyed through a bath containing a reduced dye, thenpassing thematerial so treated through a second reduced' dye bath of lessconcentration, passing the material from the second iso bath into abathhaving a considerably reduced temperature. and passing the cooledmaterial into a reducing bath containing no dye maintained at anelevated' temperature in order to insure a uniform distribution of yreduced dye upon the material.

6. A process for applying vat dyes whichv comprises absorbing a reducedvat dye by dipping material to be dyed into a hath containing thereduced dye, then while the dye is in a substantially reduced statepassing the material so treated through a second re-v duced dye bath,and oxidizing the reduced dye on the material.

.7. A process for applying vat dyes which` comprises passing thematerial to he dyed through a. bath containing a reduced dye', thenpassing the material so treated through dye,

a second reduced dye bath of less concentration, passing the materialfrom the second bath into a bath having a considerably reducedtemperature, passing the cooled material into a reducing bath.containing no maintained at an elevated temperature in order to insure auniform distribution of reduced dye upon the material, subjecting thematerial so treated to an oxidizing bath containing a bicliromate landthen washing the material to 'rid it of 4oxidizing and other impurities.

8. A process for applying vat dyes which comprises passing the materialto be dyed intoa reduced dye bath containing a dye more easily oxidizedthan-indigo of such limited dimensions and at such a rate that the dyeliquor is removed before it has a chance to oxidize in the bath. thebath being heated to approximately 120 F., and then quickly-I coolingthe material so treated by immersion in a medium at a lower temperature.

9. A process for applying vat dyes which comprises passing piece goodsto be dyed into a bath, containing a dye more easily oxidized thanindigo. reduced by hydrosullite, of such limited dimensions and at sucha rate that the dye liquor is removed before it has a chance to oxidizein the bath, and, substantially Without oxidation of the dye on thematerial prior to absorption` passing the material so treated through asecond bath also reduced 'by hydrosulfite and containing the samedyestufl in less concentration, cooling the material so treated, andrereducing the material so treated in a bath free from dyestuti'.

10. A process for applying vat dyes which comprises reducing anindanthrene dye with an alkaline hydrosultite. maintaining the dye bathcontaining these materials at approximately 120 F., passing the materialto be dyed through this solution contained in a shallow bath of suchdimensions and at such a rate that oxidation of the reduced indanthrenedye substantially does not occur in the bath, then passing the materialso treated through a second bath containing a much smaller proportion ofthe same indanthrenel dye reduced by alkaline hydrosulfite andmaintained at a temperature of approximately 120 F.. and then coolingthe material so treated by passing through Water at approximately 70 F..then passing the cooled material through a reducing bath conwhileabsorption of the dye liquor takes place then passing the goods Whlle.the vat dye is in a substantially reduced state into a second bath ofthe same reduced vat dye4 but of far less concentration than the firstbath, and chilling thegoods so treated to oppose oxidation of the goodson standing in the air.

12. A process for applying vat dyes which comprises dipping piece goodsinto a reduced vat dye\bath containing a dye more easily oxidized thanindigo of such limited dimensions and at such a rate that the dye liquoris removed before it has a chance to oxidize in the bath, and'replenishing the liquor in the bath as it is removed by the piece goods.

13. A process for applyin vat dyes which comprises dipping piece goodsinto a reduced vat dyef bath of such limited dimensions and at such arate that the dye liquor is re. moved before it has a chance to oxidizein the bath, replenishing the liquor in the bath rate that the dyeliquor is removed before it has a chance to oxidizev in the bath,replenishng the liquor in the bath as it is removed by the plece goods,and passing the material under a stream of reduced dye liquor whileabsorption takes place, then removing excess dye liquor and then passingthe material so treated while t e d'ye is in a substantially reducedstate of such limited dimen` into a second bath of reduced dye of less4v concentration that the rst bath.

Signed at Wappingers Falls, N. Y., Feb.

MERLIN. E. TICE. l

